<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <script src="my.js" type="text/javascript"></script>
    <script>
        function fun(){
            alert(1121313);
        }
    </script>
</head>
<body>
<div style="color:red;">123</div>
<button onclick="alert('你好吗')">点击我</button>
<button onclick="fun();">欢迎</button>
</body>
</html>